With Long-Term Evolution (LTE) becoming more commonly used, data services are increasingly enlarging their capacities in mobile networks. Particularly, with the rapid prevalence of smartphones, data traffics of various real-time multi-media services, such as web browsing, video streaming, on-line gaming, and real-time video communicating, are explosively increasing.
For such services, superior Quality of Service (QoS) is desired so as to provide highly reliable and high quality audio, video, and data services. In addition, priority control in smaller units, such as the units of service classes and specific users, is also required.
Methods of controlling packet priority in a path from a wireless base station to a core network device in a mobile network include methods of using Type of Service (ToS), DiffServ Code Point (DSCP), and Class of Service (CoS).
ToS enables setting of eight-level priority using 3 bits of a ToS field in the Internet Protocol (IP) header. DSCP enables setting of 64-level priority using 6 bits by redefining the same ToS field in the IP header as a DS field. Further, CoS enables setting of eight-level priority using 3 bits of the priority field of a VLAN tag in a VLAN (Virtual Local Area Network) of IEEE (The Institute of Electrical and Electronics Engineers, Inc.) 802.1Q.
Mobile networks use VLANs or the like for isolating networks. In VLANs, each VLAN is identified by a VLAN-ID as an identifier of the VLAN. The VLAN-ID identifies up to the maximum of 4,095 VLANs using 12 bits in a VLAN tag.
PTL 1 discloses base stations that can assure the quality of Voice over Internet Protocol (VoIP) in a mobile network and a router that integrally controls the base stations.
According to the technique disclosed in PTL 1, a base station and a router are connected by a multi-link group that transfers VoIP packets and a multi-link group that transfers data packets other than VoIP. Then, the base station and the router isolate a transmission line by referring to the Type of Service (ToS) region of a received packet and transmit only a VoIP packet through the dedicated line. In this way, VoIP quality can be assured in the mobile network by preventing transmission delay of VoIP packets even when a large volume of data packets are received.
Further, PTL 2 discloses a technique of relieving the shortage of VLAN-IDs in a large scale data center.
The technique disclosed in PTL 2 is a technique that relieves the shortage of VLAN-IDs in a cloud system where a plurality of cloud bases are linked by connecting with one another via Virtual Private Networks (VPNs).
According to PTL 2, each cloud base has a virtual machine, a transfer device, and a gateway device. The transfer device transfers packets using identification information of an OpenFlow technique, instead of VLAN-IDs that identify VLANs allocated for respective tenants. The gateway device transmits/receives packets to/from the VPN terminal device using VLAN-IDs and transmits/receives packets to/from the transfer device using the above-described other identification information. In this way, packet transmission and reception using VLAN-IDs and packet transmission and reception without using VLAN-IDs can be isolated, which localizes the range where VLAN-IDs are uniquely allocated and relieves the shortage of VLAN-IDs.